Miniature, two-dimensional thin-film micro-batteries are known in the art. For example, U.S. Pat. Nos. 5,338,625 and 5,567,210, whose disclosures are incorporated herein by reference, describe a thin-film microbattery used as a backup or primary integrated power source for electronic devices. The battery includes a lithium anode, an electrochemically-stable electrolyte and a vanadium-oxide cathode. The battery is fabricated directly onto a semiconductor chip, onto a semiconductor die, or onto a portion of a chip carrier.
U.S. Pat. No. 6,610,440, whose disclosure is incorporated herein by reference, describes microscopic batteries that are integratable or integrated with micro-electromechanical (MEMS) systems or other microscopic circuits. The inventors describe closed system microscopic batteries used for internal storage of electricity using interval reactants. The batteries comprise microscopic electrodes, electrolyte and a reservoir for the electrolyte.
A three-dimensional thin-film microbattery is described in U.S. Pat. No. 6,197,450, whose disclosure is incorporated herein by reference. Thin-film micro-electrochemical energy storage cells (MEESC) such as microbatteries and double-layer capacitors (DLC) are described. The energy storage cells comprise two thin layer electrodes, an intermediate thin layer of a solid electrolyte and an optional fourth thin current collector layer. The layers are deposited in sequence on a surface of a substrate. The substrate comprises multiple through-cavities of arbitrary shape, with high aspect ratio, which increase the total electrode area per volume ratio.
Three-dimensional microbatteries are also described by Long et al., in “Three-Dimensional Battery Architectures,” Chemical Review, volume 10, number 104 (October, 2004), pages 4463-4492, which is incorporated herein by reference.
Geometric configurations of 3D microbatteries are described by Hart et al., in “3-D Microbatteries,” Electrochemistry Communications, volume 5 (2003), pages 120-123, which is incorporated herein by reference. This paper presents finite-element simulations showing current and potential distribution for several cathode-anode array configurations.
A method for producing arrays of cavities in silicon is described by Kleimann et al., in “Formation of Wide and Deep Pores in Silicon by Electrochemical Etching,” Materials Science and Engineering B, volume 69-70 (2000), pages 29-33, which is incorporated herein by reference. Another process for producing micro-cavity arrays is described by Li et al., in “Microfabrication of Thermoelectric Materials by Silicon Molding Process,” Sensors and Actuators A, volume 108 (2003), pages 97-102, which is incorporated herein by reference. The authors describe a process for fabricating thermoelectric micro-modules with densely-aligned, fine-scale and high-aspect-ratio elements.
U.S. Patent Application Publication 2009/0142656, whose disclosure is incorporated herein by reference, describes an electrical energy storage device, which includes a substrate formed so as to define a multiplicity of micro-containers separated by electrically-insulating and ion-conducting walls. A first plurality of anodes is disposed in a first subset of the micro-containers, and a second plurality of cathodes is disposed in a second subset. The anodes and cathodes are arranged in an interlaced pattern.